As shown in FIG. 1, a prior art thin film solar cell is illustrated generally as 8 and comprises a transparent insulating substrate 1, a transparent electrically conductive layer 2 formed on one surface thereof which serves as a front electrode, an amorphous silicon semiconductor layer 6 which is composed of a p-type amorphous silicon layer 3, an i-type amorphous silicon layer 4 and a n-type amorphous silicon layer 5, and an aluminum layer 7 which serves as a back electrode.
This configuration is used as a photoelectric conversion device capable of being produced at a relatively low cost. Such an amorphous silicon solar cell 8 is designed so that light 9 enters the solar cell through the transparent insulating substrate 1 and is absorbed mainly by the i-type amorphous silicon layer 4. Electricity is generated between two electrodes, the transparent electrically conductive layer 2 and the aluminum layer 7, and the electricity is led out of the solar cell by a conductor 10.
These solar cells are presently used as cells for electric calculators or as cells for watches. However, it is anticipated that such cells will soon be used for power generation after improvements in (1) the photoelectric conversion efficiency, (2) enlargement of the surface area and (3) in reductions to the cost.
If amorphous silicon solar cells are to be used for power generation, larger surface areas will be required. Accordingly, such cells will have to be installed on the rooftop or wall of a house, building, factory or other installation. However, if glass is to be used as the substrate for amorphous silicon solar cells installed in such a place, there is a possible danger that the glass plate of the solar cell will be broken, for example, when hail stones hit the solar cell. Further, there is always a possible danger that the glass plate may be broken during handling in the production of the solar cell, or during its transportation or installation. The possibility of danger particularly increases when the thickness of the glass plate is less than 3 mm, or when the surface area of the glass plate is enlarged.